Gen3 wall charger, 3-phase install question

[Toads]

Hi all, have a 2023 MYP that I want to home charge.
I have a new 3-phase board. I plan on buying 16mm2 (4C+E) cable to run from the board to the Gen 3 wall charger.

My question is, what size 3-pole breaker do I install, 32A or 60A ?

I’ve been reading online that 60A is good to support the 16mm2 cable however the manual says 32A.
Bit confused.

If I’m limited to 32A breaker is the 16mm2 overkill?

 

[mongo]

Hi all, have a 2023 MYP that I want to home charge.
I have a new 3-phase board. I plan on buying 16mm2 (4C+E) cable to run from the board to the Gen 3 wall charger.

My question is, what size 3-pole breaker do I install, 32A or 60A ?

I’ve been reading online that 60A is good to support the 16mm2 cable however the manual says 32A.
Bit confused.

If I’m limited to 32A breaker is the 16mm2 overkill?

View attachment 989775

It looks like the installation manual has carry over 60A references from the North American single phase setup. You likely need a 32 amp breaker and minimum 6mm^2 wire, but I'm not sure. You might need an isolator also.
Previous thread on the topic:
Australian EV Home Charger install regulations

 

[Nevyn72]

32A 4 pole RCD.
Isolator not required but desirable if the charger is a long way from the main circuit board.

If you need to be asking these questions maybe you should be using a properly qualified sparkie...

 

[Vostok]

My question is, what size 3-pole breaker do I install, 32A or 60A ?

Also note that the HPWC charges at a maximum of 11 kW on 3-phase, which is 16A per phase (even if the internal DIP switches are set to 32A). The breaker on ours is 32A per phase and the wiring is 6mm2. Note the size of the cabling required also depends on the length of the run - it’s not a fixed size for given Amps. Get a decent sparky to install it, you don’t want to guess with stuff like this.

 

[Nevyn72]

Also note that the HPWC charges at a maximum of 11 kW on 3-phase, which is 16A per phase (even if the internal DIP switches are set to 32A). The breaker on ours is 32A per phase and the wiring is 6mm2. Note the size of the cabling required also depends on the length of the run - it’s not a fixed size for given Amps. Get a decent sparky to install it, you don’t want to guess with stuff like this.

Not quite, the Gen3 can charge at up to 22kW (32A on 3-Phase), it's the Model 3/Y that's limited to 11kW.
If you want to future proof the charger for potential alternative vehicles get it wired for 32A.

 

[Toads]

Thanks for the reply guys. Yeah it actually does look like 60A reference was on older manuals!

This makes it simple, I can get away with 6mm2 4C+ E for my 22m run. This will also future proof me somewhat as the size can support 42A.
I’ll check with my sparky about the isolation switch, my meter box is only 12m away.
Correct with using 4-pole 32A type A + 16mA breaker

 

[Vostok]

I’ll check with my sparky about the isolation switch, my meter box is only 12m away.

There seems to be differing views on whether isolation switches are mandatory or not in this situation. Some say it is mandatory under all circumstances, others say it is recommended but not mandatory.

I think if you cannot directly see the HPWC’s breaker in the meter box when standing next to the HPWC, you should install an isolation switch.

 

[paulp]

Also note that the HPWC charges at a maximum of 11 kW on 3-phase, which is 16A per phase (even if the internal DIP switches are set to 32A). The breaker on ours is 32A per phase and the wiring is 6mm2. Note the size of the cabling required also depends on the length of the run - it’s not a fixed size for given Amps. Get a decent sparky to install it, you don’t want to guess with stuff like this.

My model S charges 32a per phase 3 phase, so the restriction must be model 3/Y. I never use it though. My preferred charge speed is 10-15a, depending on the available sunshine.

 

[raynewman]

Also note that the HPWC charges at a maximum of 11 kW on 3-phase, which is 16A per phase (even if the internal DIP switches are set to 32A). The breaker on ours is 32A per phase and the wiring is 6mm2. Note the size of the cabling required also depends on the length of the run - it’s not a fixed size for given Amps. Get a decent sparky to install it, you don’t want to guess with stuff like this.

Unless you are charging an early model S with dual chargers; then it charges at 32 AMP three phase and you will need a 60 odd amp fuse.

 

[Toads]

Unless you are charging an early model S with dual chargers; then it charges at 32 AMP three phase and you will need a 60 odd amp fuse.

Which is where I was getting confused. Was getting conflicting model S info for my model Y.

I used this cable calculator for my cable run distance, and considers voltage drop etc.

Cable Size Calculator AS/NZS 3008

Cable size calculator for current rating, voltage drop, loop impedance, earth cable and short circuit, based on Australia and New Zealand standard AS/NZS 3008.

www.jcalc.net

 

[MickyD]

If you need to be asking these questions maybe you should be using a properly qualified sparkie...

I’m glad someone said it…

 

[locksmack]

How far is the cable run?

Likely you can do 6mm2 with a 32A breaker, unless the cable run is quite long.

But to echo others - get a professional to do it.

 

[FlyingKiwi]

Personally I'd be asking the sparky to install a 40A breaker and 6mm² (or 10mm² depending on if its being run in insulated walls etc) cable in case you eventually upgrade to a car with 22kW onboard charger. The breaker should be larger than the max continuous load, not equal to it.

 

[locksmack]

The breaker should be larger than the max continuous load, not equal to it.

Got a source for this? The breaker should be sized to protect the circuit. If it's too much larger then it won't be effective.

 

[raynewman]

Got a source for this? The breaker should be sized to protect the circuit. If it's too much larger then it won't be effective.

Gota cover the loss in the cable too.

 

[FlyingKiwi]

Got a source for this? The breaker should be sized to protect the circuit. If it's too much larger then it won't be effective.

Breaker is sized to prevent a short from igniting your wiring/house, not to protect the device on the end of the wire. (Most domestic 10A sockets are on a 16A or 20A breaker) Standard breakers are rated for 80% of their rated current continuously.

https://www.pdl.co.nz/faq/fa104355#:~:text=100%25%20rated%20circuit%20breakers%20can,mounted%20only%2C%20with%20special%20suffix

https://blog.se.com/datacenter/architecture/2014/06/12/clearing-confusion-80-vs-100-rated-circuit-breakers/

 

[cafz]

Gota cover the loss in the cable too.

Circuit breakers trigger on current, and current isn't "lost".

The reason they can be higher than the load is that the CB is sized to protect the cable not the load.

 

[locksmack]

Breaker is sized to prevent a short from igniting your wiring/house, not to protect the device on the end of the wire

Yep, I know. Oversizing the breaker can cause it to delay tripping in the event of a short. You shouldn't be installing a 100% rated 40A breaker when the wiring can only handle 32A.

 

[FlyingKiwi]

Yep, I know. Oversizing the breaker can cause it to delay tripping in the event of a short. You shouldn't be installing a 100% rated 40A breaker when the wiring can only handle 32A.

Unless I'm mistaken std breakers aren't 100% rated?

 

[locksmack]

Unless I'm mistaken std breakers aren't 100% rated?

I'm not too sure. My sparky put in a breaker marked as 32A and 18 months later it has never tripped despite long 32A charging sessions.

Comes back to the general advice to OP - get an electrician to do it. For the sake of a few hundred $, don't risk burning down your house and insurance refusing to pay.